The explosive growth in the volume and variety of multi-media telecommunication applications continues to drive speed demands for internet traffic and motivate research in backbone fiber-optic communication links. Coherent communications and electronic digital signal processing (DSP)-based receivers have been accepted in recent years as the next-generation standards for long-haul systems due to their flexibility, scalability and ability to compensate for various transmission impairments, including fiber nonlinearity. As fiber nonlinearity places a limit on achievable spectral efficiency, large effective-area (Aeff) single-mode fibers (SMFs) have been designed for reducing nonlinearity penalties.
However, the spectral efficiency of an optical fiber increases slowly with increasing effective area, so another solution is needed to increase system capacity.